Some nudist ran down beach (6)
I believe the answer is:
strand
'beach' is the definition.
(beach can mean to become stranded on a beach)
'some nudist ran down' is the wordplay.
'some' indicates a hidden word (some parts of the word are used).
'STRAND' is hidden in the letters of 'nudist ran down'.
(Other definitions for strand that I've seen before include "Beach; London road" , "Drive (ship) aground" , "Ply" , "A thread or a sea shore" , "Lock of hair" .)